diff --git a/source/ArmarXGui/applications/ArmarXGui/ArmarXMainWindow.cpp b/source/ArmarXGui/applications/ArmarXGui/ArmarXMainWindow.cpp
index 777cf9e5d78abab4d77aeab4acaf0ee6dd1f8514..3325b7d051e08c0047fb3842949e511e77276656 100644
--- a/source/ArmarXGui/applications/ArmarXGui/ArmarXMainWindow.cpp
+++ b/source/ArmarXGui/applications/ArmarXGui/ArmarXMainWindow.cpp
@@ -93,6 +93,7 @@
 #include <QtSvg/QSvgRenderer>
 
 #include <unistd.h>
+#include <optional>
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <sstream>